AKI Flashcards
Different stages of an AKI
Stage 1- Creatinine raised by 1.5-1.9 of baseline or urine output <0.5ml/kg/hr for 6 hours.
Stage 2 - Serum creatinine 2x the baseline or urine output <0.5ml/kg/hr for24 hours.
Stage 3 - Serum creatine 3x the baseline or creatinine >354 or or urine output <0.3ml/kg/hr for 24 hours.
Definition of an AKI
Increase in serum creatinine by ≥26.5 µmol/l within 48 h, or
Increase in serum creatinine ≥ 1.5x the baseline within the last 7 days, or
Urine volume < 0.5 ml/kg/h for 6 hours
What are the prerenal causes of an AKI?
Hypovolaemia and hypotension (could be due to diarrhoea/vomiting, inadequate fluid intake, blood loss)
Reduced effective circulatory volume (cardiac failure or sepsis)
Drugs such as ACEi or NSAIDs.
Renal artery stenosis
Renal causes of an AKI
- Glomerulonephritis,
- Acute tubular necrosis,
- Acute intertitial nephritis
- Rhabdomyolysis,
- Tumour lysis syndrome,
- Vasculitis
Post renal causes of an AKI
Obstruction eg, kidney stones in ureter, BPH, external compression of the ureter
What are the causes of acute tubular necrosis?
Ischaemia: shock or sepsis.
Nephrotoxins: Aminoglycosides, myoglobin, NSAIDs, radiocontrast agents and lead
What are the features of acute tubular necrosis?
AKI and muddy brown casts in the urine
What are the features of acute interstitial nephritis?
Clinical - Fever, rash, arthralgia, Eosinophilia, Mild renal impairment, Hypertension
On investigations - sterile pyuria and white cell casts
What are some risk factors for development on an AKI?
CKD,
Organ failure/chronic disease,
History of AKI,
Nephrotoic drugs,
Iodinated contrast,
age > 65 years old,
oliguira
What are the signs and symptoms of an AKI?
Reduced urine output,
Pulmonary and peripheral oedema,
Arrythmias secondary to changes in potassium.
Features of uraemia
What are the investigations for an AKI?
U&Es
Urinalysis,
ABG- look for acidosis
ECG to look for hyperkalaemia changes
Imaging - Renal ultrasound if unknown cause or at risk of obstruction
